Mailbox unavailable or not local error messages – Plesk

If you receive this error when adding a domain:

Unable to send notification: mail() failed: SMTP server response: 550 Requested action not taken: mailbox unavailable or not local

then you need to add a valid mailbox to your Plesk admin setup. To resolve this issue log into Plesk and click on:

Server
Edit (under personal information)
Replace the email address with a valid, working address.

Keep in mind this error shouldn’t prohibit you from creating a site, it is just notifying you that the “site created” email will not be sent.

cPanel required ports list

Cpanel required ports list

PortServiceProtocolDirectionNotes
20ftptcpinbound/outbound
21ftptcp,udpinbound/outbound
22sshtcpinbound
25smtptcpinbound/outbound
26smtptcpinbound/outbound
37rdatetcpoutbound
43whostcpoutbound
53DNStcp/udpinbound/outbound Inbound only needed if you run your own DNS server
80httptcpinbound/outbound
110pop3tcpinbound
113identtcpoutbound
143imap4tcpinbound
443httpstcpinbound
465smtptcp/ssl, tcp/udpinbound/outbound
873rsynctpc/udpoutbound
993imap4ssl tcpinbound
995pop3ssl tcpinbound
2082cpaneltcpinbound
2083cpanelssl tcpinbound
2086whmtcpinbound
2087whm ssltcpinbound
2089cp licensetcpoutbound
2095webmailtcpinbound
2096webmailssl tcpinbound
3306mysqltcpinboundOnly if you need to connect remotely
6666chattcpinbound

Disabling SMTP Tweak – cPanel

The SMTP tweak will prevent users from bypassing the mail server to send mail (this is a common practice used by spammers). It will only allow the MTA (mail transport agent), mailman, and root to connect to remote SMTP servers.  In order words, users will need to use ‘localhost’ as their SMTP server for local mailing scripts to sent mail (source).  SMTP Tweak can be enabled or disabled in the ‘Security Center’ of WHM, or from command line using:

/scripts/smtpmailgidonly on|off